JP5109087B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module.

  In the field of optical communication using light as an information transmission medium, an optical module including an optical element that mutually converts an optical signal and an electrical signal is used to receive or transmit an optical signal transmitted through an optical fiber or the like. ing. A surface emitting element typified by a vertical cavity surface-emitting laser (VCSEL) is used for the conversion from an electrical signal to an optical signal, and a PIN is used for the conversion from an optical signal to an electrical signal. A surface light receiving element typified by a photodiode is used. These optical elements are electrically connected to the substrate, and optical fibers and the like are optically connected to the optical elements.

  Such an optical module has an optical transmission body such as an optical fiber from the viewpoint of workability when optical wiring such as an optical fiber is performed on a wiring board (printed wiring board or board), and ease of maintenance and replacement. It is desirable to be detachable via a connector.

  In addition, when an optical fiber or the like is attached to or detached from the optical element, a structure for attaching or detaching the optical fiber or the like around the component on which the optical element is mounted should be provided if it is configured to be attached or detached horizontally with respect to the wiring board. Since it cannot be obtained, there is a problem that other parts cannot be mounted in the space, and the mounting density cannot be increased. Therefore, it is desirable that attachment / detachment of an optical fiber or the like can be performed in a direction perpendicular to the wiring board.

Conventionally, in order to meet such demands, an optical element is mounted so that its light emitting / receiving surface is horizontal with respect to the wiring board, and a reflection mirror is provided on the end face of an optical fiber or the like to vertically align the optical axis. There has been proposed an optical module that optically connects an optical fiber or the like and an optical element so as to be detachable in a vertical direction by using a connector converted into (see Patent Document 1).
JP 2006-65358 A

  In the optical module that optically connects the optical fiber and the like to the optical element in the vertical direction as described above, various electronic parts including the optical element are mounted on the upper structure which is a connector of the optical fiber or the like. An optical fiber or the like is optically aligned with the optical element mounted on the substrate. Here, for example, a ceramic substrate is used as the substrate on which the electronic component is mounted, and a substrate on which the electronic component or the like is mounted by applying electric wiring such as internal wiring to the ceramic substrate is used. However, the optical module is required to be manufactured at a low cost. Thus, the work of applying the internal wiring to the ceramic substrate is not only complicated, but there is a limit to the positioning accuracy for optical connection.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to provide an optical module capable of manufacturing an optical module with easy optical connection at low cost.

  The present invention is characterized by the following.

The first is an optical module that optically connects an optical transmission path that transmits an optical signal and an optical element that converts the optical signal into an electrical signal or converts the electrical signal into an optical signal. An optical transmission body that forms a path , and an upper structure including a holding member that holds the optical transmission body in a curved manner so that the optical axis on the outer side and the optical axis on the optical element side are substantially perpendicular to each other When disposed on the wiring board, an electronic component mounting board of the electronic component is mounted, including internal wirings light element to the insert molded resin substrate, provided around the electronic component mounting board on the wiring board When the upper structure is fitted and mounted on the electronic component mounting board so as to overlap vertically, the upper structure is pushed down and held by elasticity, and the optical transmission path of the upper structure and the electronic and the optical element of the component mounting board is optically connected, and the upper Electronic component mounting board to be pushed down through the concrete body, characterized in that it comprises a fitting member which is constructed as to be connected to the wiring board and electrically pressed against the wiring board.

  Secondly, in the first invention, the positioning portion where the optical transmission body of the upper structure and the optical element of the electronic component mounting substrate are positioned and optically connected is formed of a resin substrate of the electronic component mounting substrate. It is formed integrally.

  Thirdly, in the second invention, the resin component of the electronic component mounting substrate is formed with a cavity on which the electronic component is mounted and surrounded by a wall portion standing on the periphery, and the upper structure is When the upper structure is disposed on the electronic component mounting substrate, the upper surface of the resin substrate of the electronic component mounting substrate comes into contact with the upper surface of the resin substrate, so that the optical transmission body of the upper structure and the optical element of the electronic component mounting substrate are It is positioned vertically and optically connected.

  According to the first invention, by adopting the resin substrate, the internal wiring can be integrally formed by insert molding of the metal body at the time of resin molding of the resin substrate. An optical module with improved positioning accuracy for connection can be manufactured at low cost.

  According to the second aspect of the invention, the positioning portion where the optical transmission body of the upper structure and the optical element of the electronic component mounting substrate are positioned and optically connected is formed integrally with the resin substrate of the electronic component mounting substrate. By doing so, in addition to the effect of the first aspect of the invention, an optical module in which the positioning accuracy for optical connection is further improved can be manufactured at low cost.

  According to the third invention, the cavity surrounded by the wall portion standing on the periphery is formed in the resin substrate of the electronic component mounting board, so that the effects of the first invention and the second invention are achieved. In addition, an optical module in which the optical transmission body of the upper structure and the optical element of the electronic component mounting substrate are positioned in the vertical direction and can be optically connected with higher accuracy can be manufactured at low cost. .

In this specification, the “optical transmission body” includes an optical fiber made of glass or resin, an optical waveguide made of resin, or the like. In the following embodiment, an example using an optical fiber will be described. However, the optical transmission body applied in the present invention is not limited to this, and various types of optical transmission lines such as an optical waveguide can be configured. Things can be applied.
The “optical element” includes not only one having a single light receiving and emitting surface, but also one having a plurality of light receiving and emitting surfaces arranged in an array or the like. Specific examples of the optical element include a surface light emitting element such as a VCSEL and a surface light receiving element such as a PIN photodiode. The surface light emitting element and the light receiving and emitting surfaces of the surface light receiving and emitting elements are integrated in an array. It may be a thing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are perspective views showing an optical module according to an embodiment of the present invention. FIG. 1 shows a state in which the optical connection and the electrical connection are disconnected, and FIG. 2 shows a state in which the optical connection and the electrical connection are made. Yes.

As shown in FIG. 1, the optical module 1 of this embodiment includes an upper structure 5 in which an optical fiber 7 is held by a holding member 6, an electronic component mounting board 30 on which an optical element 40 is mounted, and anisotropic conductivity. A sheet 60 and a fitting member 50 fixed on a wiring board 70 (printed wiring board or board) are provided.

In this optical module 1, an anisotropic conductive sheet 60 is disposed in an opening 51 in a fitting member 50 on a wiring substrate 70, an electronic component mounting substrate 30 is disposed thereon, and an upper structure is formed thereon. 2 is fitted vertically as shown in FIG. 2, and the optical fiber 7 of the upper structure 5 and the optical element 40 of the electronic component mounting substrate 30 are optically connected, and the electronic component mounting substrate 30 and the wiring are connected. The substrate 70 is electrically connected via the anisotropic conductive sheet 60. Here, on the side surface portion of the fitting member 50, side plate portions 53 that are bent vertically from the center portions of the four sides of the opening portion 51 and extend upward are provided upright, and these side plate portions 53 are formed as upper structures. The outer peripheral portion of the holding member 6 comes into contact with the upper structure 5 when the upper structure 5 is mounted, thereby restricting the horizontal position of the upper structure 5. The mounted optical module 1 shown in FIG. 2 constitutes a compact module having a width of 10 mm × 10 mm and a thickness of 6.4 mm, for example.

3A is a perspective view of the upper structure 5, and FIG . 3B is a cross-sectional view. In the upper structure 5, a tape fiber 8 in which a plurality of (in this embodiment, 12) optical fibers 7 are arranged in parallel enters the holding member 6 from the back surface of the resin-made holding member 6. Thus, the optical fiber 7 is bent into an arc shape, and the end surface 7a of the optical fiber 7 is vertically exposed from the lower surface of the holding member 6 as shown in FIG.

  A pair of shoulder portions 12 forming a tapered surface along the peripheral edge portion are provided on both peripheral edge portions parallel to the optical fiber 7 on the upper surface of the holding member 6, and are fitted into the fitting member 50 of FIG. 1. The pair of protrusions 52 provided on the upper portion of the fitting member 50 abuts against the shoulder 12 of the holding member 6 and presses downward.

Further, as shown in FIG. 1, the holding member 6 is provided with two positioning holes 11, which are erected on the electronic component mounting substrate 30 when fitted into the fitting member 50 of FIG. The positioning pins 42 thus inserted are inserted into the positioning holes 11 of the holding member 6 so that the upper structure 5 and the electronic component mounting board 30 are positioned in the horizontal direction.

  The holding member 6 includes an upper member 10 and a lower member 20 as shown in FIGS. 3A and 3B, and the optical fiber 7 is sandwiched between the upper member 10 and the lower member 20. It comes to hold. On the lower surface side of the upper member 10, guide grooves having a V-shaped cross section, for example, are provided in parallel on a curved surface corresponding to the arc shape of the optical fiber 7, and the optical fiber 7 is 1 in each of these guide grooves. Each book is arranged and guided. On the other hand, an optical fiber holding surface having a curved surface corresponding to the arc shape of the optical fiber 7 is provided on the upper surface side of the lower member 20, and by sandwiching the optical fiber 7 between the upper member 10 and the lower member 20, The optical fiber 7 is held in a state bent in an arc shape between the guide groove of the upper member 10 and the optical fiber holding surface of the lower member 20.

  4 is a top perspective view of the electronic component mounting board 30, and FIG. 5 is a cross-sectional view. As shown in FIG. 4, the electronic component mounting substrate 30 includes a box-shaped resin substrate 31 in which a wall portion 32 as a positioning portion 90 is erected on the outer peripheral edge, and the front side on the resin substrate 31. The optical element 40 in which the same number of light receiving and emitting surfaces as the optical fiber 7 are arranged side by side is mounted. The optical element 40 includes a VCSEL as a surface light emitting element and a PIN photodiode as a surface light receiving element. The upper surface 32a of the wall portion 32 forms an optical reference surface, and the end surface 7a of the optical fiber 7 and the optical element 40 are positioned in the vertical direction by contacting the lower surface of the upper structure 5. Here, the material used for the resin substrate 31 is not particularly limited as long as it has insulation and high thermal conductivity. For example, PPS (polyphenylene sulfide) resin, PBT (polybutylene terephthalate) resin, polyamide The thing which mix | blended inorganic fillers, such as calcium carbonate and a silica, with thermoplastic resins, such as resin, can be mentioned.

  A driver integrated circuit device 41 of the optical element 40 is mounted behind the optical element 40 on the resin substrate 31, and the optical element 40 and the driver integrated circuit device 41 are connected by a bonding wire. In addition, other electronic components are mounted on the resin substrate 31, and the electronic components on the resin substrate 31 are connected to the internal wiring of the resin substrate 31 directly below the electronic components or via the electric wiring 33. And electrically connected to a back surface electrode provided on the back surface of the resin substrate 31 with a pitch of 500 μm, a diameter of 300 to 350 μm, and a height of 10 μm.

  At positions on both sides of the optical element 40 on the resin substrate 31, a pair of resin positioning pins 42 having a protruding height of 2 mm and a protruding portion diameter of 0.7 mm is provided as a positioning portion 90. By inserting the positioning pins 42 into the positioning holes 11 of the upper structure 5, the electronic component mounting substrate 30 and the upper structure 5 are positioned in the horizontal direction. The positioning pins 42 are formed integrally with the resin substrate 31.

  As shown in FIG. 5, the electronic component mounting substrate 30 has electronic components mounted in a cavity 34 surrounded by a wall portion 32, and the optical element 40 has a raised step surface 36 on the bottom surface of the cavity 34. It is installed. That is, the step surface 36 on which the optical element 40 is mounted is raised from the bottom surface 35 on which other electronic components such as the driver integrated circuit device 41 are mounted, and the upper structure 5 is placed on the wall portion of the electronic component mounting substrate 30. When the optical connection is made by contacting the upper surface 32a of the upper structure 32, the vertical distance between the end surface 7a of the optical fiber 7 of the upper structure 5 and the optical element 40 is such that the upper surface 32a of the wall portion 32 of the electronic component mounting substrate 30 is. Are defined by the step surface 36.

  Further, by providing the wall portion 32 on the electronic component mounting substrate 30, other electronic components such as the driver integrated circuit device 41 mounted on the bottom surface 35 lower than the step surface 36 do not protrude upward from the wall portion 32. Thus, the upper structure 5 is brought into contact with the upper surface 32a of the wall portion 32 of the electronic component mounting substrate 30 so that optical connection can be made.

  The height of the stepped surface 36 from the bottom surface 35 can be set to an appropriate height in consideration of the coupling efficiency of the optical connection and the like, and is not particularly limited. For example, it should be several μm to several hundred μm depending on conditions. Can do. The step surface 36 is formed when the resin substrate 31 is molded.

  The above resin substrate 31 can be manufactured by, for example, mold resin molding. Internal wiring is formed by insert molding of a metal body during resin molding. The electric wiring 33 and the back electrode on the surface of the resin substrate 31 are realized by forming a thin film by means of pressure bonding, vapor deposition, plating, or the like.

  When the optical module 1 is assembled from the state where the optical connection and the electrical connection are disconnected as shown in FIG. 1 to the state where the optical connection and the electrical connection are made as shown in FIG. 2, first, the optical module 1 is fixed on the wiring board 70 of FIG. The anisotropic conductive sheet 60 is disposed in the opening 51 of the fitting member 50 that has been made. Next, the electronic component mounting board 30 is disposed thereon, and the upper structure 5 is vertically fitted into the fitting member 50 from above.

  At this time, the positioning pins 42 of the electronic component mounting board 30 are inserted into the positioning holes 11 of the upper structure 5, and the upper structure 5 is in a horizontal direction with respect to the electronic component mounting board 30 with a predetermined accuracy, for example, 3 to 5 μm. In addition, the side surface of the holding member 6 is regulated by the side plate portion 53 of the fitting member 50, and the electronic component mounting substrate 30 is indirectly positioned in the horizontal direction with respect to the wiring substrate 70. Solder bumps having a pitch of 500 μm and a diameter of 300 to 350 μm are formed on the wiring board 70, and a pitch of 500 μm and a diameter of 300 to 350 μm provided on the lower surface of the electronic component mounting board 30 are formed against these solder bumps. The back electrode is aligned.

  Then, the upper structure 5 is pressed downward by the elasticity of the fitting member 50, whereby the anisotropic conductive sheet 60 is pressurized and becomes conductive. Thereby, the back electrode of the electronic component mounting substrate 30 and the solder bump on the wiring substrate 70 are electrically connected via the anisotropic conductive sheet 60.

Further, the positioning pins 42 of the electronic component mounting substrate 30 are inserted into the positioning holes 11 of the upper structure 5, whereby the end surface 7 a of the optical fiber 7 and the optical element 40 are horizontally aligned as shown in the sectional view of FIG. 6. In addition to the positioning in the direction, the lower surface 6a of the holding member 6 and the upper surface 32a of the wall portion 32 of the electronic component mounting substrate 30 come into contact with each other, so that the end surface 7a of the optical fiber 7 and the optical element 40 are perpendicular to each other. Once positioned, they are optically connected.

  As described above, the optical module 1 is electrically and optically connected in the vertical direction in the state shown in FIG. 2 and is capable of transmitting and receiving optical signals transmitted to the outside through the optical fiber 7. The

For example, during maintenance replacement, the optical connection can be easily disconnected by pulling out the upper structure 5 vertically from the fitting member 50, and then the electronic component mounting substrate 30 is removed from the anisotropic conductive sheet 60. Electrical connection can be easily disconnected by taking out vertically.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above embodiment, as the positioning portion 90, a pair of positioning pins 42 are provided at positions on both sides of the optical element 40 on the resin substrate 31, and positioning holes corresponding to these positioning pins 42 are provided in the upper structure 5. 11 is provided, but the number, position, shape, and the like of the positioning pins are not particularly limited. For example, a pair of positioning holes may be provided at positions on both sides of the optical element 40 on the resin substrate 31, and a pair of positioning pins corresponding thereto may be provided in the upper structure 5. A groove having a V-shaped cross section may be provided, and a V-shaped protrusion corresponding to the groove may be provided on the upper structure 5 or a combination thereof. When the cross-sectional V-shaped groove and the corresponding cross-sectional V-shaped protrusion are employed as the positioning portion 90, the upper structure 5 and the electronic component mounting substrate 30 are accurately positioned in the horizontal direction and the vertical direction. The end face of the optical transmission body of the structure 5 and the optical element 40 of the electronic component mounting substrate 30 can be effectively optically connected. Positioning pins and V-shaped projections as positioning portions 90 formed on such a resin substrate 31 are made of resin, and are integrally formed when the resin substrate 31 is molded. Further, even when the positioning portion 90 formed on the resin substrate 31 is a positioning hole or a V-shaped cross section, it is formed when the resin substrate 31 is molded.

  Further, in the above embodiment, as shown in FIG. 7A, the light is applied to the stepped surface 36 raised to the adjacent surface 81 on which the other electronic component 80 is mounted in the cavity 34 of the electronic component mounting substrate 30. Although the element 40 is mounted, depending on the relative thickness of the optical element 40 and the other electronic component 80, as shown in FIG. The optical element 40 may be mounted on the stepped surface 36 that is lowered from the adjacent surface 81 on which is mounted. Thus, by forming the step surface 36 corresponding to the relative thickness of the optical element 40 and the other electronic component 80, the upper structure 5 is not limited by the thickness of the other electronic component 80. The depth of the cavity 34 of the step surface 36 on which the optical element 40 is mounted is appropriately set according to the optical conditions for optical connection between the end face 7a of the optical fiber 7 and the optical element 40 of the electronic component mounting substrate 30. Can be set to

  In the above embodiment, the example in which the electronic component mounting board 30 and the wiring board 70 are electrically connected via the anisotropic conductive sheet 60 has been described. However, the electronic component mounting board 30 and the wiring board 70 are electrically connected to each other. The electrical connection between the electronic component mounting board 30 and the wiring board 70 can be of various structures, such as a structure in which the electronic component mounting board 30 is electrically connected to the wiring board 70 by soldering.

  In the above embodiment, the upper structure 5 is detachably mounted in the vertical direction using the fitting member 50, and the optical transmission path of the upper structure 5 is optically connected to the optical element 40 of the electronic component mounting substrate 30. However, as a mounting structure having such a function, a structure by another mechanism may be used. For example, the wiring board 70 may be provided with a fitting hole, the upper structure 5 may be provided with a latch structure, and the latch structure of the upper structure 5 may be fitted into the fitting hole of the wiring board 70 and attached. Good.

  As the optical element 40, a surface light emitting element other than a VCSEL such as a laser diode may be used, or a surface light receiving element other than a PIN photodiode may be used.

FIG. 1 is a perspective view showing an optical module according to an embodiment of the present invention, and shows a state where an optical connection and an electrical connection are disconnected. FIG. 2 is a perspective view showing a state where optical connection and electrical connection are made in the optical module of FIG. 3A and 3B are views showing the arrangement of the upper member, the optical fiber, and the lower member of the upper structure, in which FIG. 3A is a perspective view and FIG. 3B is a cross-sectional view. FIG. 4 is a perspective view of the electronic component mounting board. FIG. 5 is a cross-sectional view of the electronic component mounting board. FIG. 6 is a cross-sectional view showing a state in which the upper structure and the electronic component mounting substrate are optically connected. FIG. 7 is a partial cross-sectional view of an electronic component mounting board of an optical module according to another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical module 5 Upper structure 6 Holding member 6a Lower surface 7 Optical fiber 7a End surface 8 Tape fiber 10 Upper member 11 Positioning hole 12 Shoulder portion 20 Lower member 30 Electronic component mounting substrate 31 Resin substrate 32 Wall portion 32a Upper surface 33 Electric wiring 34 Cavity 35 Bottom surface 36 Step surface 40 Optical element 41 Driver integrated circuit device 42 Positioning pin 50 Fitting member 51 Opening part 52 Projection part 53 Side plate part 54 Projection part 60 Anisotropic conductive sheet 65a External optical axis 65b Optical element side Optical axis 70 Wiring board 80 Other electronic components 81 Adjacent surface 90 Positioning portion

Claims (3)

An optical module that optically connects an optical transmission path that transmits an optical signal and an optical element that converts the optical signal into an electrical signal or converts the electrical signal into an optical signal ,
An optical transmission body that forms an optical transmission line , and an upper portion that includes a holding member that holds the optical transmission body in a curved manner so that the optical axis on the outside side and the optical axis on the optical element side are substantially perpendicular to each other A structure ,
An electronic component mounting substrate in which an electronic component including an optical element is mounted on a resin substrate on which an internal wiring is insert-molded ;
It is provided around the electronic component mounting board on the wiring board, and when the upper structure is fitted on the electronic component mounting board so as to be stacked vertically, the upper structure is pushed down and held by elasticity. The optical component mounting board that is optically connected to the optical transmission path of the upper structure and the optical element of the electronic component mounting board and is pushed down through the upper structure is pressed against the wiring board to be connected to the wiring board. And a fitting member configured to be electrically connected to the optical module.   A positioning portion where the optical transmission body of the superstructure and the optical element of the electronic component mounting substrate are positioned and optically connected is formed integrally with the resin substrate of the electronic component mounting substrate. The optical module according to claim 1.   On the resin substrate of the electronic component mounting board, an electronic component is mounted and a cavity surrounded by a wall portion standing on the periphery is formed.When the upper structure is placed on the electronic component mounting substrate, When the upper structure is in contact with the upper surface of the wall of the resin substrate of the electronic component mounting substrate, the optical transmission body of the upper structure and the optical element of the electronic component mounting substrate are positioned vertically and optically connected. The optical module according to claim 2.

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